I used to suffer from chronic trigeminal neuralgia, and your friend is right, it’s extremely painful, inasmuch as the pain I get from nerve damage which I have been suffering for 20+ years. I had trigeminal neuralgia for several years, and it kept getting worse and more frequent with age, lasting for several hours at a stretch. No pain reliever could do anything for me, I just had to sit it out and it usually started at night. Doctors didn’t have much to suggest except that stress might be part of the cause.
Then I found an herbal remedy that did the trick. Simple celery juice! Tell your friend to take two stalks of celery and juice them up to fill a mug, nothing else. It will numb the nerves and the pain starts to disappear even as I’m drinking it down.
At my most serious, I was getting the pain as often as once every few days to a week, so I learned to keep celery stalks handy in my fridge. And then one winter, I ran out of celery and it started up in the middle of the night. I had a tiny withered stalk of Chinese celery frozen in the snow in my backyard garden, so in desperation I dug it up and juiced that one, giving me about an ounce of juice — it tasted horribly bitter, but it did the trick!
At the time, I seldom ate celery (especially Chinese celery which is extremely strong in taste), as I didn’t care for the taste, but I later found that including celery in my diet at least once a month kept the neuralgia from ever returning. I haven’t had to have the celery juice since. I think there must be some nutrient in the celery that helps with nerve health. I don’t pretend to understand it, but hey, this is way better than relying on ineffective analgesics. Just let him know to get in the habit of including celery in his diet and keep juicing lots of it until it stops re-occurring. I think regular consumption must create a cumulative effect.